GM Service Manual Online
For 1990-2009 cars only

Brake Fluid


Object Number: 809919  Size: A2

If your vehicle has hydraulic brakes, there is a brake master cylinder. Refer to the Maintenance Schedule to determine when to check your brake fluid.

Caution: Do not add brake fluid before checking the level or there could be too much brake fluid. Brake fluid could spill on the hot engine and it can catch fire. You could be burned and the vehicle could be damaged. See "Checking Brake Fluid" in this section.

Checking Brake Fluid (Hydro Max System)

Apply the brake pedal several times with the ignition off. Then clean one of the reservoir caps and the area around the cap, and remove it. The fluid level should be even with the bottom ring of the filler opening.


Object Number: 808493  Size: A3

The Hydro Max brake fluid reservoir is located in the engine compartment on the driver's side of the vehicle.

If it is low, add enough fluid to fill the reservoir to the proper level.

Checking Brake Fluid (Hydro Boost System)

Apply the brake pedal several times with the ignition off. Clean the cover and the side of the reservoir. Check to see if the fluid level inside the reservoir falls within the MIN/MAX level indicator on the side of the reservoir.


Object Number: 829822  Size: A3

The Hydro Boost brake fluid reservoir is located in the engine compartment on the driver's side of the vehicle.

If it is low, add enough fluid to fill the reservoir to the proper level.

What to Add

Use the proper fluid listed in your Maintenance Schedule. Use new brake fluid from a sealed container only.

Always clean the brake fluid reservoir cap/cover and the area around the cap/cover before removing it. This will help keep dirt from entering the reservoir.

Caution: With the wrong kind of fluid in the brake hydraulic system, the brakes might not work well. This could cause a crash. Always use the proper brake fluid.

Notice: 

   •  Using the wrong fluid can badly damage brake system parts. For example, just a few drops of mineral-based oil, such as engine oil, in your brake system can damage brake system parts so badly that they will have to be replaced. Do not let someone put in the wrong kind of fluid, and do not use DOT-5 silicone brake fluid.
   • If you spill brake fluid on your vehicle's painted surfaces, the paint finish can be damaged. Be careful not to spill brake fluid on your vehicle. If you do, wash it off immediately. See Appearance Care .

Four-Wheel Disc Brakes (Hydraulic Only)

Your vehicle has four-wheel disc brakes.

Some driving conditions or climates may cause a brake squeal when the brakes are first applied or lightly applied. This does not mean something is wrong with your brakes.

Brake linings should always be replaced as complete axle sets.

Four-Wheel and Six-Wheel Drum Brakes (Air Only)

The brake drums should be removed and inspected each time the tires are removed for rotation or changing. When you have the front brakes replaced, have the rear brakes inspected, too.

Brake linings should always be replaced as complete axle sets.

Brake Pedal Travel

See your dealer if the brake pedal does not return to normal height, or if there is a rapid increase in pedal travel. This could be a sign of brake trouble.

Brake Adjustment

Every time you make a brake stop, your brakes adjust for wear.

Replacing Brake System Parts

The braking system on a vehicle is complex. Its many parts have to be of top quality and work well together if the vehicle is to have really good braking. Your vehicle was designed and tested with top-quality GM brake parts. When you replace parts of your braking system -- for example, when your brake linings wear down and you need new ones put in -- be sure you get new approved GM replacement parts. If you do not, your brakes may no longer work properly. For example, if someone puts in brake linings that are wrong for your vehicle, the balance between your front and rear brakes can change -- for the worse. The braking performance you have come to expect can change in many other ways if someone puts in the wrong replacement brake parts.

Air Brake Systems

If your vehicle has air brakes, it is important to get rid of moisture in your system. Moisture will damage your system if it is not removed daily.

There are two ways to do this. One is automatic if your air-brake vehicle has the optional moisture ejector. If your vehicle does not have that option, you must drain the air reservoirs occasionally to be sure the air dryer is working properly.

Drain the air brakes at full system pressure. To be sure you are at full pressure, check your air pressure gage. It should read at least 100 psi (692 kPa).

Moisture Ejector

If you have air brakes with a moisture ejector, the valve automatically ejects moisture from the reserve tank when the air compressor cycles.

Air Dryer

If your vehicle has air brakes, it may have an air dryer. This collects and removes dirt, moisture or other foreign matter from the air prior to entering the brake system. It is mounted on the passenger's side frame rail.

If your dryer is a Bendix-Westinghouse, it has a filter that you need to change at intervals. See Scheduled Maintenance for more about servicing this filter.

Electric Air Compressor

Your vehicle may have an electric air compressor. This compressor is used to run options that require pressurized air, such as air horn, air seat, exhaust restrictor or an exhaust brake.

The air compressor is used when vehicles are not equipped with an air brake system.


Object Number: 808489  Size: A3

The air supply for this system must be maintained by releasing the drain valve to eject any moisture that may have built up in the system.

It is recommended that this system be drained on a weekly basis.

Clutch Pedal Free Travel

If you have a manual transmission, your clutch will need adjustment when pedal free travel gets down to about 1/4 inch (32 mm), as measured at the clutch pedal pad. You should have 1 1/2 to 2 inches (38 to 51 mm) of clutch pedal free travel. See Scheduled Maintenance for more information.

If your clutch ever needs service, be sure to use only GM clutch replacement parts.

Chassis Lubrication

Your Maintenance Schedule provides all of the required chassis lubrication intervals and identifies proper lubricants to use. Be sure to see your Maintenance Schedule before performing any chassis lubrication service. To determine location of chassis lubrication items, use the following charts.

Single Axle Models


Object Number: 829818  Size: C1

Item Number

Item

Remarks

1

Brake Camshaft**

One fitting each (apply sparingly).

2

Steering Column Slip Joint*

One fitting.

3

Steering Drag Link Ends

One fitting each end.

4

Pivot Points and Hinges

Apply chassis lubricant.

5

Pivot Points and Hinges

Apply chassis lubricant.

6

Slack Adjuster**

One fitting.

7

Brake Cam Roller Pins at interface of pin and shoe**

Apply engine oil.

8

Front Steering Knuckles

One fitting each side, lower bushing. (Hand-operated grease gun only.) Hand-pack upper bearing.

9

Front Wheel Bearings

Hand-pack or lubricate.

10

Steering Tie Rod Ends

One fitting each end.

11

Spring Slip Pads* (Multi-leaf Only)

Apply chassis lubricant.

12

Clutch Release Bearing*

Cup or fitting.

13

Battery Terminal (except "ST" type)

Keep coated with petroleum jelly.

14

Transmission

Fill to level of filler plug.

15

Propshaft Slip Joints

Lubricate with GM Part No. 1051344 Wheel Bearing Lubricant.

16

Parking Brake Clevis Pin$

Apply chassis lubricant.

17

Parking Brake Lever Pivot*, $

Apply chassis lubricant.

18

Clutch Release Cross Shaft, Master Cylinder$

Apply chassis lubricant, fill to 1/4 inch (6 mm) below opening.

19

Release Bearing, Clutch Cross Shaft

Two fittings, apply chassis lubricant.

20

Clutch Release Fork

Two fittings.

* Applies to some vehicles.

** Applies to air brakes only.

$ Applies to hydraulic brakes only.

Tandem Axle Models


Object Number: 829817  Size: B4

Item Number

Item

Remarks

1

Brake Camshafts

One fitting each.

2

Propshaft U-Joint

One fitting each joint. Lubricate with GM Part No. 1051344, Wheel Bearing Lubricant

3

Rear Axles

Fill to level of filler plug.

4

Brake Shoe

Roller Pins

Apply engine oil at pin to shoe joint only.

5

Rear Spring Pin

One fitting each side.